In conventional motor vehicles having internal combustion engines, such a freewheel mode, can be, for example, activated by turning off the internal combustion engine and/or mechanically separating it from the drive train. The available kinetic energy of the rolling vehicle can be utilized in this way, thereby saving fuel.
In hybrid vehicles having a motor unit with an internal combustion engine and at least one electric machine, a freewheel mode can also be created, for example, by turning off the internal combustion engine, separating the internal combustion engine from the drive train, and turning off the electric machine in addition, if required.
The efficiency of a freewheel mode can be reduced due to losses, which occur when a turned-off electric machine is still being turned. In contrast, the problem in the case of a mechanical separation of the electric machine from the drive train is that a corresponding elaborate coupling including an actuation apparatus and a control must be at disposal, and furthermore, that the decoupled electric machine is not available for regenerative braking.